I have a 38 Gal Freshwater tank. Currently there are 6 Mollies, 2 Platy-wags, 4 guppies, 3 Tetra and one red tail shark. Also in there are 2 snails, a fiddler crab and a Hammers cobalt blue lobster. I was told adding a small amount of salt would help the tank in general, but I don't want to hurt...